小兴安岭森林沼泽甲烷排放及其影响因子  

METHANE EMISSION FROM FORESTED SWAMPS IN XIAOXING’AN MOUNTAINS, NORTHEASTERN CHINA

作　　者：孙晓新[1] 牟长城[1] 石兰英[1] 程伟[1] 刘霞[1] 吴云霞[1] 冯登军[1] 

机构地区：[1]东北林业大学林学院,哈尔滨150040

出　　处：《植物生态学报》2009年第3期535-545,共11页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(30670349)

摘　　要：利用静态箱-气相色谱法,对小兴安岭5种森林沼泽生长季甲烷(CH4)排放通量进行研究,并探讨了温度、地下水位和植被等主要环境因子对CH4排放的影响。结果表明:毛赤杨(Alnus sibirica)沼泽、落叶松(Larix gmelinii)-藓类(Moss)沼泽和落叶松-泥炭藓(Sphagnum spp.)沼泽的CH4排放有明显的季节变化规律,而白桦(Betula platyphylla)沼泽和落叶松-苔草(Carex schmidtii)沼泽CH4通量的季节变化相对较小。落叶松-泥炭藓沼泽有爆发式CH4通量现象出现,对生长季CH4排放通量影响较大。在生长季内落叶松-泥炭藓沼泽、毛赤杨沼泽和白桦沼泽为大气CH4的源,而落叶松-苔草沼泽和落叶松-藓类沼泽为大气CH4的汇,生长季CH4的平均排放通量分别为(56.08±200.38)、(15.34±14.89)、(0.64±0.88)、(–0.88±1.76)和(–0.94±3.00)mg·m–2·d–1。除落叶松-泥炭藓沼泽外,不同森林沼泽类型间CH4排放通量随地下水位升高而增大;地下水位在–34.5～–30.8cm之间可能存在CH4源与汇的临界点,季节平均地下水位低于这一位置的森林沼泽为大气CH4的汇。温度对森林沼泽CH4通量的影响比较复杂,二者间可能为正或负的显著(p<0.05)或非显著(p>0.05)相关关系。CH4通量与乔木地上生物量有较强的负相关性,这有可能成为小兴安岭森林沼泽CH4通量的最佳预测因子。Aims Our major objectives were to quantify methane fluxes and variations during growing season and understand key factors controlling methane fluxes in five natural forested swamps. Methods We measured methane fluxes from natural forested swamps in Xiaoxing’an Mountains from early June to late October 2007, using the static opaque chamber and gas chromatography technique. Important findings We observed large seasonal variations in methane fluxes in Alnus sibirica swamp, Larix gmelinii-moss swamp and Larix gmelinii-Sphagnum spp. swamp, but smaller variations in Betula platyphylla swamp and Larix gmelinii-Carex schmidtii swamp. Episodic flux was detected in Larix gmelinii-Sphagnum spp. swamp, which greatly influenced methane fluxes during the growing season. Alnus sibirica swamp, Larix gmelinii-moss swamp and Larix gmelinii-Sphagnum spp. swamp were sources of atmospheric methane, but Betula platyphylla swamp and Larix gmelinii-Carex schmidtii swamp were sinks, and the average methane emission rates during the growing season were （56.08 ± 200.38）, （15.34 ± 14.89）, （0.64 ± 0.88）, （–0.88 ± 1.76） and （–0.94 ± 3.00 ） mg·m–2·d–1, respectively. Average methane emission rates were higher with higher water table among the forested swamps, except for Larix gmelinii-Sphagnum spp. swamp. There was a critical point of atmospheric methane source or sink when the water table was at –34.5 ～ –30.8 cm; forested swamps with average water table below this value were atmospheric methane sinks. Effects of temperature on methane fluxes were complex, as temperature may show positive or negative and significant or non-significant correlations. Aboveground biomass of trees may be the best indicator of methane emissions from these forested swamps, because there were strong negative correlations between them.

关 键 词：甲烷排放 森林沼泽 地下水位 温度 植被 

分 类 号：Q948[生物学—植物学]